Photoelectric Switch And Sensor Unit

ABSTRACT

To make a display in a photoelectric switch easy to see for a user. A photoelectric switch includes a housing having a substantially rectangular parallelepiped shape. A display is attached to a first surface of the outer surface of the housing. A control board is housed on the inside of the housing. A controller is mounted on the control board. The first surface includes a hole-like or cutout-like opening section for allowing a signal cable to pass from the outside to the inside of the housing. The signal cable electrically connects the control board disposed on the inside of the housing and the display disposed on the outside of the housing. A cover member includes a window section for exposing a display region of the display and covers a non-display region of the display. The cover member is provided outside the housing.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims foreign priority based on Japanese PatentApplication No. 2017-186813, filed Sep. 27, 2017, the contents of whichis incorporated herein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a photoelectric switch and a sensorunit.

2. Description of Related Art

A product (work) produced in a factory is conveyed by a conveyingapparatus such as a belt conveyor. Arrival of the work at apredetermined place is detected by a photoelectric switch. In general,the photoelectric switch projects light toward the work or the like,receives reflected light from the work, and displays a numerical valueindicating a light receiving amount and a threshold compared with thenumerical value on a seven-segment display (JP-A-2003-141961). Whendetecting the work on the basis of the light receiving amount and thethreshold, the photoelectric switch outputs an ON signal that indicatesthat the work is detected.

In this way, the photoelectric switch is a relatively simple sensor thatoutputs a detection signal indicating whether the work is detected.Therefore, the seven-segment display has been adopted as a display formany years. A photoelectric switch not including a display that displaysnumerical values is still present.

However, in recent years, according to the upgrading of photoelectricswitches, the seven-segment display has been unable to providesufficient information to users. Therefore, the inventors of the presentapplication examined adoption of a dot matrix display such as an OLED(organic light emitting diode). When the dot matrix display is disposedon the inside of a housing of the photoelectric switch, the distancefrom the outer edge of the housing to a display surface of the dotmatrix display increases. An impression that the display surface isdisposed in the depth is given to a user. Information displayed on thedot matrix display is less easy to for the user.

SUMMARY OF THE INVENTION

Therefore, an object of the present invention is to make a display in aphotoelectric switch easy to see for a user.

The present invention provides, for example, a photoelectric switchincluding: a housing having a substantially rectangular parallelepipedshape; a display unit attached to a first surface of an outer surface ofthe housing; a light projecting unit and a light receiving unit providedon a second surface located adjacent to the first surface; a receivingunit provided on the first surface and configured to receive operation;a display control unit configured to cause the display unit to display athreshold adjusted through the receiving unit and a signal valueindicating an amount of light received by the light receiving unit; acontrol board housed on an inside of the housing, the display controlunit being mounted on the control board; a signal cable for connectingthe control board and the display unit; and a cover member including awindow section for exposing a display region of the display unit,configured to cover a non-display region of the display unit, andprovided outside the housing.

According to the present invention, the cover member holds a displayprovided on the outer surface of the housing. Therefore, it is possibleto make the display in the photoelectric switch easy to see for a user.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a photoelectric switch;

FIGS. 2A and 2B are perspectives view showing a plurality ofphotoelectric switches coupled to one another;

FIG. 3 are an exploded view showing the photoelectric switch;

FIGS. 4A and 4B are perspective views showing the photoelectric switch;

FIG. 5 is a perspective view showing a positional relation among a covermember, a display, and a shield member;

FIGS. 6A to 6D are diagrams for explaining an upper case and the like;

FIGS. 7A to 7C are diagrams for explaining a relation between thedisplay and a signal cable;

FIGS. 8A to 8E are diagrams for explaining a position of a slit;

FIGS. 9A and 9B are diagrams for explaining the position of the slit;

FIG. 10 is a diagram showing the signal cable and the shield memberintegrated with each other;

FIGS. 11A to 11E are diagrams for explaining a relation between thedisplay and the signal cable;

FIGS. 12A and 12B are sectional views of the photoelectric switch; and

FIG. 13 is an enlarged view of a cross section of the photoelectricswitch.

DESCRIPTION OF EMBODIMENTS

An embodiment of the present invention is explained below. Theindividual embodiment explained below would be useful for understandingvarious concepts such as a superordinate concept, an intermediateconcept, and a subordinate concept of the present invention. Thetechnical scope of the present invention is decided by the claims and isnot limited by the individual embodiment explained below.

FIG. 1 is a perspective view showing a photoelectric switch. Aphotoelectric switch 1 includes a substantially rectangular housing. InFIG. 1, a z axis corresponds to a longitudinal direction, an x axiscorresponds to a latitudinal direction, and a y axis corresponds to aheight direction. The housing generally has six outer surfaces. The sixouter surfaces include an upper surface, a bottom surface, a frontsurface, a rear surface, a left side surface, and a right side surface.In FIG. 1, the upper surface, the front surface, and the right sidesurface are seen. The housing includes a lower case 2 and an upper case3. An internal space in which a control board and the like are housed isformed by fitting the lower case 2 and the upper case 3 with each other.A part of the upper case 3 forms the upper surface. A display 5, a modebutton 7, an active receiver button 8, an adjustment button 9, a slideswitch 10, a set button 11, a display lamp 24, a clamp module 14, andthe like are provided on the upper surface. The display 5 is a dotmatrix display such as an OLED and displays a threshold and a lightreceiving amount. The display 5 is held and fixed by the outer surfaceof the upper case 3 and a cover member 4. The display 5 is provided tobe offset further to the front surface side than the center of the uppersurface. The adjustment button 9 is a button for increasing and reducinga threshold and operating a menu. The menu is a menu displayed on thedisplay 5 and including various setting items for setting the operationof the photoelectric switch 1. The mode button 7 is a button forswitching an operation mode related to a light projection amount and thelike. The active receiver button 8 is a special button for projectinglight from the photoelectric switch 1 to the outside through a lightreceiving fiber. When detecting depression of the active receiver button8, the photoelectric switch 1 uses the light receiving fiber as a lightprojecting fiber and projects light toward the outside while receivinglight made incident from the outside. The projected light is not lightfor detecting work and is light for assisting optical axis adjustment bya user. Note that a light emitting element configured to output theassist light may be disposed in the center of a light receiving element.In this case, a light receiving surface of the light receiving elementis larger than a light emitting surface of the light emitting element.The slide switch 10 is a switch for selecting a set of a plurality ofsetting parameters. The set button 11 is a button for starting automaticsetting of a threshold. When detecting that the set button 11 ispressed, the photoelectric switch 1 determines a threshold according toa light receiving amount. For example, when the work is detected, thedisplay lamp 24 is lit or extinguished. The clamp module 14 is a moduleconfigured to clamp and hold the light projecting fiber and the lightreceiving fiber. A tubular hole 12 into which the light projecting fiberis inserted and a tubular hole 13 into which the light receiving fiberis inserted are provided on the front surface of the housing. An outputcable is attached to the rear surface of the housing. A cable bush 15 isa bush for holding the output cable.

A connector 16 a and coupling sections 17 a and 17 b are provided on theright side surface of the housing. FIG. 2A shows that a plurality ofphotoelectric switches 1 are respectively coupled to one another by theconnectors 16 a and the coupling sections 17 a and 17 b and fixed to aDIN rail 18. DIN is an abbreviation of Deutsches Institut für Normung.An incident end of a light projecting fiber 22 is inserted into the hole12. An emission end of a light receiving fiber 23 is inserted into thehole 13. In FIG. 2A, an open-closable upper cover 19 configured to coverthe upper surface of the housing is also shown. Note that, as shown inFIG. 2B, when the upper cover 19 has light transmissivity, a hole maynot be provided on the upper surface of the upper cover 19. This isbecause, if the upper cover 19 has light transmissivity, the user canconfirm display content of the display 5 even in a closed state of theupper cover 19. When the upper cover 19 does not have lighttransmissivity, as shown in FIG. 2A, a hole or a window may be providedon the upper surface of the upper cover 19. The upper cover 19 functionsas a dust cover. As shown in FIGS. 2A and 2B, the plurality ofphotoelectric switches 1 can be respectively laterally coupled.Therefore, the plurality of photoelectric switches 1 are calledinterconnected sensor as well.

FIG. 3 is an exploded view of the photoelectric switch 1. A decorationmember 20 may be provided on the rear end side of the upper cover 19. Arotational pin 19 a is provided on the rear end side of the upper cover19. The rotational pin 19 a fits in a holding hole 19 b provided on therear end side of the upper case 3. Consequently, the upper cover 19 isrotatably coupled to the upper case 3. To enable the user to confirminformation displayed on the display 5 even in a closed state of theupper cover 19, the upper cover 19 may be formed by a transparentmember. A backbone member 36 for supporting the display 5 is providednear the center of the upper case 3. Four fringes 47 are provided on theleft and the right of the backbone member 36. The four fringes 47 areprojecting sections projecting upward from the upper case 3. The fourfringes 47 position the display 5 in the latitudinal direction (the xdirection). Note that the four fringes 47 fit with recessed sections ofthe cover member 4. Two claw sections 48 are provided on the left andthe right of the backbone member 36. The claw sections 48 fit withrecessed sections provided on the inner side of a center leg of thecover member and fix the cover member 4 to the upper case 3. Therecessed sections may be grooves or may be through-holes. An openingsection 25 is provided on the rear end side of a display mountingsection centering on the backbone member 36. The opening section 25 is athrough-hole or a cutout for allowing a signal cable to pass from theouter surface to the inner surface side of the upper case 3. The signalcable includes a power supply line for supplying electric power to thedisplay 5 and a control line for supplying a control signal to thedisplay 5. The signal cable is connected to a control board 30. Thecontrol board 30 may be one substrate. If two substrates are provided inthe x-axis direction, the length in the x-axis direction of thephotoelectric switch 1 increases. Therefore, in this embodiment, onlyone control board 30 is provided in the x-axis direction. A controller 6such as a CPU (central processing unit) is mounted on the control board30. The controller 6 causes the display 5 to display a threshold and alight receiving amount. Switches corresponding to the adjustment button9, the mode button 7, the active receiver button 8, the slide switch 10,and the set button 11 are mounted on the control board 30. The buttonsmay be formed of resin such as POM (polyacetal). Note that the uppercover 19, the cover member 4, and the housing may be basically formed ofpolycarbonate. An LED (light emitting diode) for supplying light to alight diffusing member of the display lamp 24 is also mounted on thecontrol board 30. On the control board 30, the connector 16 a forcommunicating with adjacent another photoelectric switch 1 and receivingelectric power is provided. An element holder 26 is provided on thefront surface side of the control board 30. A light emitting element 32and a light receiving element 33 are attached to the element holder 26.The element holder 26 includes a hole for the light projecting fiber 22inserted from the hole 12 and a hole for the light receiving fiber 23inserted from the hole 13. The clamp module 14 is disposed on the frontsurface side of the element holder 26. The clamp module 14 holds thelight projecting fiber 22 and the light receiving fiber 23. A fixture 28for fixing to the DIN rail 18 and a metal cover 29 are attached to thebottom surface of the lower case 2. The metal cover 29 may play a roleof heat radiation and an electromagnetic shield.

FIG. 4A is a perspective view of the photoelectric switch 1 in a statein which the cover member 4 is fixed to the upper case 3. FIG. 4B is aperspective view of the photoelectric switch 1 in a state in which thecover member 4 is not fixed to the upper case 3. Various buttons and thedisplay 5 are fixed to the upper case 3. Further, the control board 30is fixed to the upper case 3. A signal cable 51 electrically connectedto the display 5 and the control board 30 enters the inside of thehousing passing through the opening section 25. The signal cable 51 isconnected to a connector of the control board 30. A connector 16 b isprovided on the left side surface of the control board 30. The connector16 b of the photoelectric switch 1 is a female connector. The connector16 b fits with and is electrically connected to the male connector 16 aof another photoelectric switch 1 located on the left of thephotoelectric switch 1.

Note that, as it is seen from FIG. 4A and the like, the height of theactive receiver button 8 is smaller than the heights of the mode button7 and the adjustment button 9. This is to prevent wrong operation of theactive receiver button 8.

FIG. 5 is a perspective view for explaining the cover member 4 indetail. The cover member 4 includes two front legs 42, two center legs43, and two rear legs 44. A window section 40 is provided on the uppersurface of the cover member 4. The user can view a display surface ofthe display 5 through the window section 40. The window section 40 issurrounded by four frames. A left frame 41 a and a right frame 41 b arethin compared with a front frame 41 d and a rear frame 41 c. This is tosecure a display area in the latitudinal direction of the photoelectricswitch 1. The rear frame 41 c has a large area compared with the otherframes. This is to protect, with the rear frame 41 c, for example, an ICconfigured to control the display 5. Character information and the likemay be printed on the rear frame 41 c. Because the rear frame 41 c has acertain degree of an area, even if the user presses the adjustmentbutton 9 with a finger, display information on the display 5 is lesseasily hidden by the finger. That is, the rear frame 41 c cansufficiently separate the display 5 and the buttons from each other.Note that, because the area of the front frame 41 d is small, thedisplay lamp 24 and the display 5 can be set close to each other.Consequently, information transmitting mechanisms focused by the usercan be integrated in one place. Four cutouts 46 in total are provided onthe right side surface and the left side surface of the cover member 4.The four cutouts 46 fit with the four fringes 47 provided in the uppercase 3, position the cover member 4 with respect to the upper case 3,and fixes the cover member 4 to the upper case 3. Recessed sections 45are respectively provided on the inner surface sides of the two centerlegs 43. The recessed sections 45 fit with the claw sections 48respectively provided on the right side surface and the left sidesurface of the upper case 3. A shield member 50 may be adopted toprotect the front surface, the bottom surface, the left side surface,and the right side surface of the display 5. The shield member 50includes a front wall 50 d configured to protect the front surface ofthe display 5, a bottom section 50 a configured to protect the bottomsurface of the display 5, a right wall 50 b configured to protect theright side surface of the display 5, and a left wall 50 c configured toprotect the left side surface of the display 5. The display 5 is held bythe backbone member 36 and the cover member 4 in a state in which thedisplay 5 is covered with the shield member 50. The shield member 50 isformed by an FPC (flexible printed circuit board).

FIG. 6A is a plan view showing the upper surface of the photoelectricswitch 1. As shown in FIG. 6A, a switch and a button are not provided inthe latitudinal direction of the display 5. Therefore, a dimension inthe latitudinal direction of the display 5 can be set sufficientlylarge. Note that the rear frame of the cover member 4 has an area enoughfor printing characters and the like.

FIG. 6B shows the left side surface of the upper case 3. FIG. 6C showsthe left side surface of the upper case 3 to which the control board 30is attached. A terminal 52 of the signal cable 51 extending from thedisplay 5 is connected and fixed to a connector 16 c mounted on thecontrol board 30. The signal cable 51 enters the inside from the outsideof the housing and is connected to the control board 30. Therefore, thesignal cable 51 is formed by a thin FPC cable or the like havingflexibility.

FIG. 6D shows the photoelectric switch 1 in a state in which the lowercase 2 is attached to the photoelectric switch 1. Fixing holes 63 a and63 b are provided on the left side surface of the lower case 2. Thecoupling sections 17 a and 17 b of another photoelectric switch 1located on the left of the photoelectric switch 1 are respectivelyinserted into the fixing holes 63 a and 63 b of the photoelectric switch1. Note that a hole from which the connector 16 b is exposed is providedon the left side surface of the lower case 2. In FIG. 6D, a lid 64protects the hole.

<Disposition of the Signal Cable With Respect to the Display>

FIG. 7A shows the right side surface of the display 5. The display 5 isformed by stacking a transparent member 70, an OLED layer 71, and atransparent base material 72 in the height direction. A material of thetransparent member 70 and the transparent base material 72 is atransparent substrate (a second substrate) including glass and resin. Atransparent electrode extending from the long side of the OLED layer 71and a transparent electrode extending from the short side of the OLEDlayer 71 are formed on the bottom surface of the transparent member 70and are electrically connected to a driving IC 54. The driving IC 54 isan integrated circuit configured to drive the display 5. The driving IC54 is fixed to the bottom surface of the transparent member 70 byadhesive 73. The signal cable 51 extending from the control board 30 iselectrically connected to the terminal of the driving IC 54. In thisway, the signal cable 51 is connected to an end portion in thelongitudinal direction of the display 5, that is, a terminal (aconnecting section 70 a) provided on the side of the short side of thedisplay 5. This makes it easy to secure a display area in thelatitudinal direction of the display 5. In work manufacturing andinspection sites, a plurality of photoelectric switches 1 are coupledand used. Therefore, the length in the latitudinal direction of thephotoelectric switch 1 is set to, for example, 5 mm or more or 14 mm orless. If the driving IC 54 and the signal cable 51 are attached to thelatitudinal direction of the display 5, a display region of the display5 is narrowed. That is, it is hard to read characters displayed on thedisplay 5. Therefore, it is desirable that the driving IC 54 and thesignal cable 51 are not attached to the end portion (the side of thelong side) in the latitudinal direction of the display 5.

FIG. 7B shows that the driving IC 54 is provided halfway in the signalcable 51. This would be useful for reducing the length in thelongitudinal direction of the transparent member 70. The transparentelectrode extending from the long side of the OLED layer 71 is connectedto the signal cable 51 as the terminal (the connecting section 70 a)provided on the side of the short side of the display 5.

FIG. 7C shows that the backbone member 36 of the upper case 3 is adoptedas a base material instead of the transparent base material 72. This isuseful for reducing the display 5 in thickness. That is, this is usefulfor reducing the height of the display 5. The opening section 25 isprovided in the backbone member 36. The signal cable 51 enters theinside of the housing passing through the opening 25. The driving IC 54is disposed to be located halfway in the signal cable 51 and on theinside of the housing. Note that the transparent electrode extendingfrom the long side of the OLED layer 71 and provided in the transparentmember 70 is connected to the signal cable 51 as the terminal (theconnecting section 70 a) provided on the side of the short side of thedisplay 5.

In this way, the display 5 includes the OLED layer 71 functioning as adisplay layer and the transparent member 70. The transparent electrodefunctions as a signal line extending from the OLED layer 71 toward thesignal cable 51. The transparent electrode is provided in the vicinityof the interface between the OLED layer 71 and the transparent member70. The cover member 4 covers a side surface in the vicinity of theinterface between the OLED layer 71 and the transparent member 70.Because the vicinity of the interface is easily broken, the cover member4 protects the vicinity of the interface.

<Disposition of a Cable Passing Section>

FIG. 8A is a schematic sectional view of the upper case 3. FIGS. 8B to8E are perspective views of the display mounting section. The upper case3 includes a first upper surface 38 on which the set button 11 isdisposed, a second upper surface (a front wall 37), a third uppersurface (the backbone member 36), a fourth upper surface (a rear wall35), and a sixth upper surface 34 on which the adjustment button 9 andthe like are disposed. Note that the first upper surface 38 and thesixth upper surface 34 may be called upper stage and the backbone member36 may be called lower stage. In this way, the upper surface of theupper case 3 may have a level difference. The backbone member 36 may becalled placing section. The placing section may be solid from theviewpoint of improving rigidity. As shown in FIG. 8A, the second uppersurface (the front wall 37), the third upper surface (the backbonemember 36), and the fourth upper surface (the rear wall 35) form arecessed section on a cross section extending along the longitudinaldirection of the housing. The display 5 is pressed against the wallsurface (the front wall 37) on a closer side to the second upper surfaceof the two wall surfaces forming the recessed section. According toFIGS. 8A and 8B, the opening section 25 is a slit-like hole provided onthe rear end side of the backbone member 36. This indicates that theopening section 25 may be provided on the front end side of the backbonemember 36. According to FIG. 8C, the opening section 25 is provided onthe lower side of the rear wall 35. This indicates that the openingsection 25 may be provided on the lower side of the front wall 37. Theopening section 25 may be provided in a coupling section of the backbonemember 36 and the rear wall 35 (the front wall 37). That is, a slit maybe formed to extend across the backbone member 36 and the rear wall 35(the front wall 37). FIG. 8D shows that the opening section 25 isprovided in the center of the backbone member 36. The area of theopening section 25 is smaller than the base area of the display 5. Thisis to support the bottom surface of the display 5 with the backbonemember 36. However, the bottom surface of the display 5 only has to besupported by either two long frames extending in the longitudinaldirection of the backbone member 36 or two short frames extending in thelatitudinal direction of the backbone member 36. FIG. 8E shows that thecutout-like opening section 25 is provided on the right side of thebackbone member 36. This indicates that the cutout-like opening section25 may be provided on the left side of the backbone member 36. If thesignal cable 51 is a cable that has high flexibility and is bendablelike an FPC cable, a degree of freedom of the disposition of the openingsection 25 would increase. Note that, in the case shown in FIG. 8, thesignal cable 51 would be mainly connected to the side of the long sideof the display 5. However, if the signal cable 51 is the FPC cable, itwould be also possible to allow the signal cable 51 to pass through thecutout-like opening section 25 shown in FIG. 8E by bending the signalcable 51 extending from the side of the short side of the display 5.

FIG. 9A shows the display section 25 provided at the rear end portion ofthe backbone member 36. As shown in FIG. 9A, the housing of thephotoelectric switch 1 is elongated. When focusing on the backbonemember 36, it is seen that the display mounting section is present tothe edge of the housing. This is useful for expanding the display areaof the display 5. The opening section 25 being provided on the rear endside of the backbone member 36 is also useful for expanding the displayarea of the display 5. FIG. 9B shows the signal cable 51 bent to passthrough the opening section 25. In this way, the signal cable 51 extendsfrom the outside to the inside of the upper case 3 via the openingsection 25.

<Integration of the Signal Cable With the Shield>

FIG. 10 shows the signal cable 51 configured by an FPC 60. A displaymodule including the display 5 and the driving IC 54 is also showntogether with the signal cable 51. Note that the signal cable 51 isintegrated with the shield member 50 by the FPC 60. The shield member 50includes a metal layer of copper or the like and a base film layer. Theright wall 50 b is formed by folding the FPC 60 at a right angle along afold 56 c. The left wall 50 c is formed by folding the FPC 60 at a rightangle along a fold 56 d. The front wall 50 d is formed by folding theFPC 60 at a right angle along a fold 56 e. Note that, to make it easy tofold the FPC 60, a plurality of holes 55 may be provided in the metallayer along the folds 56 c, 56 d, and 56 e. The metal layer is connectedto a ground line of the signal cable 51. Consequently, the shield member50 can protect the OLED (the display 5) from electric noise.

Further, when the FPC 60 is valley folded along a fold 56 a, the shieldmember 50 covers the bottom surface of the display 5. A portion bent ina U shape in the signal cable 51 shown in FIG. 9B is formed bysuperimposing a signal wiring section 53 a and a shield wiring section53 b in the FPC 60. That is, when the FPC 60 is valley folded along thefold 56 a, the signal wiring section 53 a and the shield wiring section53 b overlap. Further, when being inserted through the opening section25, the overlapping portion of the signal wiring section 53 a and theshield wiring section 53 b is bent in a U shape. Further, when the FPC60 is folded at a right angle along a fold 56 b, a mounting surface ofthe terminal 52 becomes parallel to the control board 30.

FIGS. 11A to 11E show a positional relation between the display 5 andthe signal cable 51. FIG. 11A is a plan view of the display 5 to whichthe signal cable 51 is connected. FIG. 11B is a diagram showing the leftside surface of the display 5. The signal cable 51 extending from therear end side of the display 5 is bent in a U shape in a superimposedsection 53 formed by superimposing the signal wiring section 53 a andthe shield wiring section 53 b. Further, when the signal cable 51 isbent at a right angle along the fold 56 b, the mounting surface of theterminal 52 becomes parallel to the control board 30. FIGS. 11C to 11Eare perspective views of the display 5. The mounting surface of theterminal 52 is parallel to the control board 30 but is orthogonal to thebottom surface of the display 5.

The terminal 52 may be configured from, for example, eight pins. A VCCpin is a pin for supplying electric power to the driving IC 54. A VSSpin is a pin connected to the ground (for providing ground potential).An RES pin is a pin for supplying a reset signal for starting andrestarting the driving IC 54 to the driving IC 54. An SCLK pin is a pinfor supplying a clock for serial communication. An SDA pin is a pin fortransmitting data for serial communication. An IREF pin is a pin foradjusting an electric current fed to the OLED layer 71. A VCOMH pin is apin for connecting an external capacitor and the driving IC 54 tostabilize an internal power supply of the driving IC 54. A VDD pin is apin for supplying a voltage for logic operation of the driving IC 54.

Note that the shield member 50 may be a shield seat configured by amember separate from the signal cable 51.

<Shield>

FIG. 12A is an A-A sectional view obtained by cutting the photoelectricswitch 1 along an A-A cut line in FIG. 6D. FIG. 12B is a B-B sectionalview obtained by cutting the photoelectric switch 1 along a B-B cut linein FIG. 6D. FIG. 13 is an enlarged view enlarging and showing a part ofFIG. 12A. As shown in FIGS. 12A and 13, claw sections 48 of the uppercase 3 are fit in the recessed sections 45 provided in the left andright center legs 43 of the cover member 4. As shown in FIGS. 12A, 12B,and 13, the height of the right wall 50 b and the height of the leftwall 50 c of the shield member 50 are respectively heights for coveringthe OLED layer 71 and the transparent base material 72 of the display 5and covering at least a part of the transparent member 70. Thetransparent member 70 and the transparent base material 72 are glass orthe like. The glass is easily broken compared with resin. Therefore, theshield member 50 protects the transparent member 70 and the transparentbase material 72 from a shock and the like. The OLED layer 71 is furtherprotected from electric noise as well by the shield member 50. Thebottom surface of the display 5 is covered by the bottom section 50 a ofthe shield member 50. The backbone member 36 prevents heat generatedfrom the control board 30 from being easily transmitted to the display5.

As shown in FIG. 12B, the distal end portions of the left and rightfront legs 42 of the cover member 4 are held by the lower case 2 and theupper case 3. Consequently, the cover member 4 is firmly fixed to thehousing.

<Summary>

As explained with reference to FIG. 1 and the like, the photoelectricswitch 1 includes the housing having the substantially rectangularparallelepiped shape. That is, the housing is elongated. The display 5is an example of a display unit attached to the outer surface, that is,a first surface of the housing. In the past, because a display is housedinside a housing of a photoelectric switch, the distance from the outersurface of the housing to the display is long and display information isless easily seen. In this embodiment, because the display 5 is attachedto the outer surface of the housing, the distance from the outer edge ofthe photoelectric switch 1 to the display 5 is short and displayinformation of the display 5 is easily seen. The light emitting element32, the hole 12, and the like are an example of a light projecting unitprovided near a second surface located adjacent to the first surface.The light receiving element 33 and the hole 13 are an example of a lightreceiving unit provided near the second surface located adjacent to thefirst surface. The adjustment button 9 and the like are an example of areceiving unit provided on the first surface or the display unit andconfigured to receive user operation. The controller 6 is an example ofa display control unit configured to cause the display unit to display athreshold adjusted through the receiving unit and a signal valueindicating an amount of light received by the light receiving unit. Thecontrol board 30 is an example of a control board (a first substrate)housed on the inside of the housing, the display control unit beingmounted on or connected to the control board. The signal cable 51 is anexample of a signal cable for connecting the control board 30 and thedisplay 5. As shown in FIGS. 6A to 6C, the display 5 includes aconnecting section connected to the signal cable 51. The connectingsection of the display 5 is disposed between the display region and thesignal cable 51 in the longitudinal direction of the housing. Note that,as shown in FIGS. 7A to 7C and FIG. 10, the display 5 has two shortsides and two long side. The signal cable 51 may be connected to theside of one short side of the two short side. Consequently, a connectionstructure of the signal cable 51 capable of securing a sufficientdisplay area concerning the display 5 in the photoelectric switch 1 isprovided.

The display unit may include a dot matrix display and a driving circuitconfigured to drive the dot matrix display. The display 5 is an exampleof the dot matrix display. The driving IC 54 is an example of a drivingcircuit. As shown in FIG. 7A and the like, the driving IC 54 is providedat the end portion in the longitudinal direction of the display 5. Thesignal cable 51 is connected to the driving IC 54. That is, the drivingIC 54 may be provided between the display 5 and the connecting sectionin the longitudinal direction of the housing. Note that the display 5and the driving IC 54 may be disposed on the same member. According toFIG. 7A, the OLED layer 71 of the display 5 and the driving IC 54 aredisposed on the transparent member 70.

As shown in FIGS. 11B and 11C, the signal cable 51 may include a firstportion for connecting the display 5 and the driving IC 54 and a secondportion for connecting the driving IC 54 and the control board 30. Asshown in FIG. 10, the signal cable 51 may be an FPC cable. Consequently,it is easy to connect the display 5 disposed on the outside of thehousing and the control board 30 disposed on the inside of the housing.

The housing may include the upper case 3 and the lower case 2. In thiscase, the first surface is the upper surface of the upper case 3.

According to the present invention, the opening section 25 is providedon the outer surface, in particular, the upper surface of the housing.The opening section 25 makes it possible to dispose the signal cable 51from the inside to the outside of the housing and makes it possible toattach the display 5 to the outer surface of the housing. That is, thesignal cable 51 is connected to the control board 30 via the openingsection 25. Because the display 5 is provided on the outer surface ofthe housing, an impression that the display 5 is disposed in the depthis less easily given to the user. Therefore, the display 5 is easilyseen for the user. The side of the short side of the display 5 to whichthe signal cable 51 is connected may be the side of the short sidefarther from the second surface (the front surface of the display 5) ofthe two short sides of the display 5. In this case, the opening section25 may be provided, for example, on the rear end side of the backbonemember 36. The side of the short side of the display 5 to which thesignal cable 51 is connected may be the side of the short side closerfrom the second surface (the front surface) of the two short sides ofthe display 5. In this case, the opening section 25 may be provided, forexample, on the front end side of the backbone member 36. Note that thebackbone member 36 of the upper case 3 is supported by the control board30. This is useful for improvement of the rigidity of the housing.Further, the thickness of the backbone member 36 set larger than thethickness of the other portions of the upper case 3 improves theconfiguration of the upper case 3 itself. In particular, the increase inthe rigidity of the backbone member 36 makes it easy to protect thedisplay 5.

As explained with reference to FIGS. 8A to 8E and the like, the firstsurface (the upper surface) of the upper case 3 includes the openingsection 25. The opening section 25 functions as a hole-like orcutout-like passing section for allowing the signal cable 51 to passfrom the outside to the inside of the housing. As shown in FIG. 8B andthe like, the opening section 25 may be a slit provided along thelatitudinal direction (the x-axis direction) of the first surface. Asshown in FIG. 8E and the like, the opening section 25 may be a slitprovided along the longitudinal direction (the z-axis direction) of thefirst surface. As shown in FIG. 7C, the driving IC 54 may be housed onthe inside of the housing. This reduces the dimension of the mountingsection of the display 5. As shown in FIG. 1 and the like, thelongitudinal direction of the display 5 and the longitudinal directionof the first surface are parallel.

As shown in FIG. 5 and the like, the cover member 4 is adopted as aholding member configured to hold the display 5 provided on the outersurface of the housing. Consequently, it is possible to dispose thedisplay 5 on the outer surface of the housing. Information displayed onthe display 5 is easily seen for the user. By disposing the cover member4 on the outer side of the housing in this way, it is possible toincrease the display region of the display 5. However, when the display5 is provided on the outer surface of the housing, the display 5 easilyreceives a shock from the outside. Therefore, the cover member 4 plays arole for protecting the display 5. Further, as shown in FIGS. 5 and 10and the like, the shield member 50 is an example of a shield memberprovided in at least a part of the side surface of the display 5. Asshown in FIG. 13 and the like, the cover member 4 is an example of acover member configured to sandwich the shield member 50 between theside surface of the display 5 and the cover member 4 and cover at leasta part of the side surface of the display 5. In this way, the shieldmember 50 also plays a role for protecting the display 5 from a shock.

As shown in FIG. 5, the cover member 4 may include a window section 40configured to expose the display region of the display 5. The covermember 4 may be configured to cover a non-display region of the display5. The non-display region is a portion on which information is notdisplayed in the upper surface of the display 5.

The thickness of one frame (e.g., the right frame 41 b or the left frame41 a) located at the end portion in the longitudinal direction of thewindow section 40 among the four frames located around the windowsection 40 in the cover member 4 is larger than the thickness of twoframes (e.g., the front frame 41 d and the rear frame 41 c) located atboth ends in the latitudinal direction of the window section 40. Thismakes it easy to secure a display area in the latitudinal direction ofthe display 5. The cover member 4 may be configured to engage withprojecting sections projecting from the first surface. For example, theprojecting sections (the fringes 47) projecting from the upper surfaceof the upper case 3 may engage with the cutouts 46 of the cover member4.

The shield member 50 may be electrically connected to the ground line ofthe signal cable 51. Consequently, the shield member 50 reduces theinfluence of electric noise on the display 5.

As shown in FIG. 13, the length of the short side of the first surfaceof the upper case 3 is substantially equal to a sum of the length of theshort side of the display 5, the thickness of the side surfaces (thecenter legs 43) located at both the ends in the latitudinal direction ofthe cover member 4, and the thickness of the shield member 50 (the rightwall 50 b and the left wall 50 c). Consequently, it is possible to bringthe length in the latitudinal direction of the display 5 close to thelength in the latitudinal direction of the upper surface of thephotoelectric switch 1 while protecting the display 5 with the shieldmember 50. That is, it is easy to increase the size of charactersdisplayable on the display 5.

As shown in FIG. 10, the signal cable 51 and the shield member 50 may bean integrated FPC cable. Consequently, it is possible to reduce thenumber of components. It is easy to integrate the ground line to theshield member 50 with the signal cable 51.

As shown in FIGS. 10 and 11B, the FPC cable may be bent at least in onepart. Further, a part of the shield member 50 and a part of the signalcable 51 may overlap.

The shield member 50 may include a first region (the bottom section 50a) configured to cover the bottom surface of the display 5, a secondregion (the right wall 50 b) configured to protect a first side surfaceof the display 5, a third region (the left wall 50 c) configured toprotect a second side surface of the display 5, and a fourth region (thefront wall 50 d) configured to protect a third side surface of thedisplay 5. As shown in FIG. 10, the second region, the third region, andthe fourth region may be connected to the first region.

The upper cover 19 is an example of an openable lid configured to coverthe receiving unit and the display 5 covered by the cover member 4.Consequently, oil droplets and the like generated in the factory lesseasily adhere to the adjustment button 9 and the display 5. Breakage ofthe adjustment button 9 and the display 5 would less easily occur. Thecover member 4 is a cover configured to cover a part of the display 5and provided on the outer side of the first surface of the housing. Asshown in FIGS. 6B and 9B, the height of the upper surface of the covermember 4 and the height of a surface on which the receiving unit isprovided of the first surface may be substantially the same in theheight direction of the housing.

As shown in FIG. 1 and the like, the opening section 25 may be coveredby the cover member 4 or the display 5. Consequently, foreign mattersless easily intrude into the inside of the housing through the openingsection 25.

Characters may be written on the surface of one frame (e.g., the rearframe 41 c) located at the end portion in the longitudinal direction ofthe window section 40. For example, when a transmissive fiber is used,there are operation modes such as D-ON (dark on) for lighting thedisplay lamp 24 when work is detected and L-ON (light on) forextinguishing the display lamp 24 when work is detected. In this case,the display 5 may display a mark (e.g., an arrow mark) indicating one of“L-ON” and “D-ON” printed on the rear frame 41 c. The rear end of thedisplay 5 and the rear frame 41 c are adjacent. Therefore, the display 5may display display information associated with information displayed onthe rear frame 41 c.

As shown in FIG. 7A, the display 5 may include a transparent member (thetransparent member 70), an OLED (the OLED layer 71) provided on thelower surface side of the transparent member, and a base material (thetransparent base material 72 and the backbone member 36) provided on thelower surface side of the OLED. The cover member 4 is provided toprotect at least the OLED layer 71. Consequently, breakage of the OLEDlayer 71 and the influence of electric noise are reduced.

As shown in FIG. 13, the thickness of the cover member 4 is smaller thanthe thickness of the housing (the upper case 3 and the lower case 2).Consequently, it is possible to increase the length in the latitudinaldirection of the display 5 as much as possible. It is possible toincrease the surface area of the display 5. It is possible to increasethe size of characters displayed on the display 5.

In the embodiment explained above, the photoelectric switch 1 is adoptedas an example of the sensor unit. However, the sensor unit may be asensor unit configured to detect other physical quantities such as apressure sensor. The light receiving element 33 is an example of adetecting unit. However, the light receiving element 33 may be adetection element configured to detect a physical quantity (e.g., alight receiving amount or pressure) detected from a detection target andoutput a detection signal according to the physical quantity. Thedisplay 5 is an example of a display unit configured to display thephysical quantity detected by the detecting unit. The display lamp 24and the output cable to the outside are an example of an output unitconfigured to output a comparison result of the physical quantitydetected by the detecting unit and a threshold. The adjustment button 9is an example of a receiving unit and an operation unit configured toreceive adjustment operation for the threshold. The adjustment button 9is an example of a threshold adjusting unit configured to adjust athreshold. The controller 6 is an example of a display control unitconfigured to cause the display unit to display, in a display region ofthe display unit, the threshold adjusted through the receiving unit anda signal value indicating the physical quantity detected by thedetecting unit. The connecting section of the display 5 is disposedbetween the adjustment button 9 and the display region (the OLED layer)of the display 5.

As shown in FIG. 3, the lower case 2 is a lower case having a concaveshape in section opened in an upper surface. The upper case 3 is anupper case configured to put a lid on the upper surface of the lowercase 2. The housing of the photoelectric switch 1 is formed by the uppercase 3 and the lower case 2. The control board 30 is an example of afirst substrate. The control board 30 is housed in the lower case 2 toface a third surface located adjacent to the first surface and thesecond surface. The first surface is the upper surface of the upper case3. The third surface is, for example, the coupling sections 17 a and 17b. More strictly, the third surface is one of inner surfaces forming thelower case 2.

What is claimed is:
 1. A photoelectric switch comprising: a housinghaving a substantially rectangular parallelepiped shape; a display unitattached to a first surface of an outer surface of the housing; a lightprojecting unit and a light receiving unit provided on a second surfacelocated adjacent to the first surface; a receiving unit provided on thefirst surface and configured to receive operation; a display controlunit configured to cause the display unit to display a thresholdadjusted through the receiving unit and a signal value indicating anamount of light received by the light receiving unit; a control boardhoused on an inside of the housing, the display control unit beingmounted on the control board; a signal cable for connecting the controlboard and the display unit; and a cover member including a windowsection for exposing a display region of the display unit, configured tocover a non-display region of the display unit, and provided outside thehousing.
 2. The photoelectric switch according to claim 1, wherein thefirst surface includes a hole-like or cutout-like opening section forallowing the signal cable to pass from an outside to an inside of thehousing, and the opening section is covered by the cover member or thedisplay unit.
 3. The photoelectric switch according to claim 2, whereincharacters are written on a surface of one frame located at an endportion in a longitudinal direction of the window section.
 4. Thephotoelectric switch according to claim 1, further comprising a shieldmember configured to cover at least a part of a side surface of thedisplay unit, wherein the cover member sandwiches the shield memberbetween the cover member and the side surface of the display unit andcovers at least a part of at least the side surface of the display unit.5. The photoelectric switch according to claim 4, wherein the shieldmember is electrically connected to a ground line of the signal cable.6. The photoelectric switch according to claim 4, wherein length of ashort side of the first surface is substantially equal to a sum oflength of a short side of the display unit, thickness of side surfaceslocated at both ends in a latitudinal direction of the cover member, andthickness of the shield member.
 7. The photoelectric switch according toclaim 4, wherein the signal cable and the shield member are anintegrated FPC cable.
 8. The photoelectric switch according to claim 7,wherein the FPC cable is bent at least in one part, and a part of theshield member and a part of the signal cable are laid one on top ofanother.
 9. The photoelectric switch according to claim 7, wherein theshield member includes a first region for covering a bottom surface ofthe display unit, a second region for protecting a first side surface ofthe display unit, a third region for protecting a second side surface ofthe display unit, and a fourth region for protecting a third sidesurface of the display unit, and the second region, the third region,and the fourth region are connected to the first region.
 10. Thephotoelectric switch according to claim 4, wherein thickness of oneframe located at an end portion in a longitudinal direction of thewindow section among four frames located in a periphery of the windowsection in the cover member is larger than thickness of two frameslocated at both ends in a latitudinal direction of the window section.11. The photoelectric switch according to claim 1, wherein the covermember is configured to engage with a projecting section projecting fromthe first surface.
 12. The photoelectric switch according to claim 1,wherein the display unit includes a dot matrix display and a drivingcircuit disposed in the non-display region and configured to drive thedot matrix display.
 13. The photoelectric switch according to claim 1,further comprising an openable lid configured to cover the receivingunit and the display unit covered by the cover member.
 14. Thephotoelectric switch according to claim 2, wherein the first surfaceincludes an upper stage and a lower stage, the opening section isprovided in the lower stage, and the receiving unit is provided in theupper stage.
 15. The photoelectric switch according to claim 1, whereinthe display unit includes a display layer and a transparent member, anda signal line extending from the display layer to the signal cable isprovided near an interface between the display layer and the transparentmember, and the cover member covers a side surface near the interfacebetween the display layer and the transparent member.
 16. Aphotoelectric switch comprising: a housing having a substantiallyrectangular parallelepiped shape; a display unit attached to a firstsurface of an outer surface of the housing; a light projecting unit anda light receiving unit provided on a second surface located adjacent tothe first surface; a receiving unit provided on the first surface andconfigured to receive operation; a display control unit configured tocause the display unit to display a threshold adjusted through thereceiving unit and a signal value indicating an amount of light receivedby the light receiving unit; a control board housed on an inside of thehousing, the display control unit being mounted on the control board; asignal cable for connecting the control board and the display unit; ashield member provided in at least a part of a side surface of thedisplay unit; and a cover member configured to sandwich the shieldmember between the cover member and the side surface of the display unitand cover at least a part of at least the side surface of the displayunit.
 17. The photoelectric switch according to claim 16, wherein thecover member includes a window section for exposing a display region ofthe-display unit and is configured to cover a non-display region of thedisplay unit.
 18. The photoelectric switch according to claim 1, whereinthe display unit includes a transparent member, an OLED provided on alower surface side of the transparent member, and a base materialprovided on a lower surface side of the OLED, and the cover member isprovided to protect at least the OLED.
 19. The photoelectric switchaccording to claim 1, wherein thickness of the cover member is smallerthan thickness of the housing.
 20. A sensor unit comprising: a housinghaving a substantially rectangular parallelepiped shape; a display unitattached to a first surface of an outer surface of the housing; adetecting unit provided on a second surface located adjacent to thefirst surface and configured to output a detection signal according to aphysical quantity detected from a detection target; a receiving unitprovided on the first surface and configured to receive operation; adisplay control unit configured to cause the display unit to display athreshold adjusted through the receiving unit and a signal valueindicating the physical quantity detected by the detecting unit; acontrol board housed on an inside of the housing, the display controlunit being connected to the control board; a signal cable for connectingthe control board and the display unit; and a cover member including awindow section for exposing a display region of the display unit,configured to cover a non-display region of the display unit, andprovided outside the housing.